# How to calculate the number of device charges using a Power Bank or Power Station.

Are you looking to determine how many times you can charge your device (laptop, iPad, drone etc.) using a Power Bank or Power Station? Understanding this calculation can help you plan your power usage and ensure that your devices stay charged on the go. In this guide, we'll walk you through the process of calculating the number of device charges using a simple formula.

The Formula:

(Number of Device Charges) = (Power Source Capacity in Watt-hours × 0.85) / Device Battery Capacity in Watt-hours

Do you want to know how often you can charge your phone with a Power Bank? In our blog “How often can I charge my phone with a Power Bank?” we give a more practical formula. Do you want to know the charging times of other devices? Keep reading!

## 1. Gather the Necessary Information

Before you start calculating, make sure you have the following information:

• The capacity of your Power Bank or Power Station in Watt-Hours (Wh). This information can usually be found on the product packaging, user manual or online.

• The capacity of your device's battery in Watt-Hours (Wh). This information can often be found on the device itself, in its specifications or online.

## 2. Understand the Variables

• Watt-Hours (Wh): This measurement represents the total amount of energy a battery or power source can store or deliver over time. It’s calculated by multiplying the voltage (V) by the capacity (Ah) of the power source.

• The 0.85 factor used in the formula accounts for various energy losses and inefficiencies that occur during the process of charging a device with a Power Bank.

## 3. Plug in the Values

Now that you have the required data, you can use the formula to calculate the number of device charges. Plug in the values:

(Number of Device Charges) = (Power Source Capacity × 0.85) / Device Battery Capacity

Multiply the Power Bank or Power Station Capacity by 0.85 and then divide the result by the Device Battery Capacity. This will give you the approximate number of times you can charge your device with the Power Source.

## Example

Let's say you have a Power Bank with a capacity of 100Wh and a device with a battery capacity of 30Wh.

(Number of Device Charges) = (100Wh × 0.85) / 30Wh

(Number of Device Charges) = 85Wh / 30Wh

(Number of Device Charges) ≈ 2.83

In this example, the Power Bank can approximately charge the device 2.83 times. 